Maximizing Suspension Performance - CHP How It Works

Matt Jones: Front-to-rear and left-to-right weight distribution is heavily determined by how a vehicle is designed from the factory. Moving components around within the chassis for the ideal static weight distribution is best, but adding ballast isn’t preferable if a minimum weight rule applies. Before ballast is added to correct left-to-right imbalances, the builder must first determine if the extra weight added to correct the imbalance will outweigh the shortcomings of additional overall vehicle weight. Just about every vehicle can benefit from a 50/50 left-right distribution, as this will help equalize grip in left and righthand turns. However, the same can’t be said for front-to-rear weight distribution. In my opinion, slightly adjusting front/rear weight distribution should typically be done for tuning rather than adding weight to hit the magic 50/50 figure. Drag cars, of course, can benefit from more rear bias since little is needed from the front tires.

Wedge

John Hotchkis: Wedge or reverse-wedge simply refers to intentionally biasing the crossweight of a car to help it turn in one direction. If the right-front-to-left-rear crossweight is greater than 50 percent, a car has wedge. If it’s less than 50 percent, then it has reverse-wedge. Since oval track cars only turn left, they run wedge to assist with corner exit speed. This is also done in conjunction with running lots of positive camber on the inside tire. The result is a car that’s so weight jacked in one direction that they don’t even drive straight down the straightaways. You actually have to turn the wheel to the right to get them to turn straight. Although that’s an extreme example, for cars that turn left and right you usually want to get the crossweight as close to 50 percent as you can, even if the road course or autocross that you’re on has more right turns than left turns, or vice versa. Typically, whatever you’ll gain turning in one direction by biasing the crossweight will be overshadowed by the decrease in handling when turning in the opposite direction. If a car turns right more than it turns left, then setting the camber differently on the right front tire is a much better alternative than biasing the crossweight. The next step is tuning a car to the racing surface with tire pressure and shock valving adjustments. CHP